This invention relates to satellite broadcast systems, and more particularly to a method and apparatus for reducing deep fading of signals transmitted from terrestrial repeater stations used in such systems.
Terrestrial repeater stations are used as part of conventional satellite-based communications systems to amplify and re-transmit channel encoded signals as they travel from a satellite to their intended final destination, such as a mobile receiver. Typically, a plurality of repeater are employed to provide good signal coverage in a particular metropolitan area.
FIG. 1 shows a diagram of a conventional repeater station 10 in which a receive antenna 11 receives an RF signal from a satellite. The received signal is then filtered by a baseband filter 12 before being amplified first by a low-noise amplifier 13 and then by a high-power amplifier 14. The amplified signal is then transmitted by a transmit antenna 15 to its intended final destination.
Conventional satellite-based communications systems which employ terrestrial repeater stations suffer from a significant drawback. Specifically, since each one of the repeater stations transmit identical signals, these signals often destructively add together forming an interference pattern that severely degrades the quality of the signal received at its intended final destination. The periods of time during which such interference prevents strong, clear signals from being received is commonly referred to as deep fading.